Browsing by Author "Ignat, M"

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    Delamination of brittle films on polymeric substrates
    (Engineers Australia, 2005-02-16) Latella, BA; Ignat, M; Triani, G
    Miniaturisation in microelectromechanical systems (MEMS) and continuing advances in fabrication of functional and complex thin film structures approaching the nanoscale has seen adhesion and mechanical stability as key issues. The reliability of thin film-substrate systems when subjected to externally applied stresses is strongly influenced by the intrinsic film properties and the associated interfacial adhesion characteristics. Accordingly, understanding the fracture damage and adhesion performance of thin films to applied stresses is crucial. Using micro-mechanical in-situ tensile experiments it is possible to detect and analyse the critical conditions for cracking and decohesion of the thin film. In this work it will be shown that these types of experiments offer new insights into evaluating mechanical response and interfacial adhesion using a titanium oxide thin film on polycarbonate as the model system. © 2005 Engineers Australia
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    Enhanced adhesion of atomic layer deposited titania on polycarbonate substrates
    (Elsevier, 2007-01-22) Latella, BA; Triani, G; Zhang, Z; Short, KT; Bartlett, JR; Ignat, M
    Interfacial adhesion of atomic layer deposited titania films on polycarbonate substrates with and without a water-plasma treatment has been studied using in situ observation during microtensile testing. Specific attention is paid to multiple tension-generated transverse cracks in the titania films when subjected to externally applied uniaxial tensile stresses. The strength, fracture toughness and interfacial adhesion of the titania film on polycarbonate were deduced from theoretical models based on experimentally determined parameters. The tensile tests were conducted in a micromechanical tester positioned under an optical microscope allowing in situ viewing of cracking damage. The strain to initiate first cracking and the crack density as a function of strain were obtained. The in situ observations indicated different interfacial behaviour between water-plasma-treated and non-treated samples. It is shown that the water plasma treatment drastically improves the adhesion of the titania film to polycarbonate. Calculations show that the fracture energy required for film debonding in the plasma-treated polycarbonate is 5.9 J/m2 compared to 2.5 J/m2 for the untreated sample. A simple chemical structure model was used to explain the observed differences. © 2007, Elsevier Ltd.
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    Mechanical stability of a Ti02 coating deposited on a polycarbonate substrate
    (Routledge, 2005) Ignat, M; Getin, S; Latella, BA; Barbé, CJ; Triani, G
    The demands imposed on mechanical durability of film-substrate systems in many leading technologies (particularly microelectronics, photonics and biomaterials) are becoming more stringent and, thus, associated problems have to be understood and solved. Film-substrate systems are subjected to internal stresses, caused by thermoelastic mismatch, or to external mechanical stresses applied monotonically or cyclically. When reaching critical levels, these stresses may activate damage mechanisms such as cracking and de-adhesion of the film. Identifying these failures and understanding the critical conditions which cause them is essential, prior to any technological application of the system. © 2005 CRC Press